Waitsburg is a city in Walla Walla County, Washington, United States. The population was 1,217 at the 2010 census. Waitsburg has a unique city classification in Washington state, being the state's only city which still operates under its territorial charter.

Pendleton is a city and the county seat of Umatilla County, Oregon. The population was 17,107 at the time of the 2020 census, which includes approximately 1,600 people who are incarcerated at Eastern Oregon Correctional Institution.Pendleton is the smaller of the two principal cities of the Hermiston–Pendleton Micropolitan Statistical Area. This micropolitan area covers Morrow and Umatilla counties and had a combined population of 92,261 at the 2020 census.

The Tri-Cities are three closely linked cities (Kennewick, Pasco, and Richland) at the confluence of the Yakima, Snake, and Columbia Rivers in the Columbia Basin of Eastern Washington. Each city borders one another, making the Tri-Cities seem like one uninterrupted mid-sized city. The three cities function as the center of the Tri-Cities metropolitan area, which consists of Benton and Franklin counties. The Tri-Cities urban area consists of the city of West Richland, the CDPs of West Pasco and Finley, as well as the CDP of Burbank, despite the latter being located in Walla Walla County. The official 2016 estimate of the Tri-Cities MSA population is 283,846, a more than 12% increase from 2010. 2016 U.S. MSA estimates show the Tri-Cities population as over 300,000. The combined population of the three principal cities themselves was 193,567 at the 2010 Census. As of April 1, 2016, the Washington State Office of Financial Management, Forecasting Division estimates the cities as having a combined population of 217,430.The Tri-Cities Airport is located in Pasco and provides the region with commercial and private air service. Pasco is the seat of Franklin County, while the other two cities are located in Benton County. In 2010, Kiplinger rated the Tri-Cities among the Top 10 best places to raise a family, and CNN/Money ranked the Tri-Cities one of the top 10 best bets for gains in housing value, due to its relatively stable economic conditions since the early 2000s.

Union County is one of the 36 counties in the U.S. state of Oregon. As of the 2010 census, the population was 25,748. Its county seat is La Grande.Union County comprises the La Grande, OR Micropolitan Statistical Area. It is one of the eight counties of eastern Oregon.